Multi-layer film device and method

ABSTRACT

A device, structure, and method are provided whereby an insert layer is utilized to provide additional support for weaker and softer dielectric layer. The insert layer may be applied between two weaker dielectric layers or the insert layer may be used with a single layer of dielectric material. Once formed, trenches and vias are formed within the composite layers, and the insert layer will help to provide support that will limit or eliminate undesired bending or other structural motions that could hamper subsequent process steps, such as filling the trenches and vias with conductive material.

BACKGROUND

In the current process of miniaturizing semiconductor devices, low-kdielectric materials are desired as the inter-metal and/or inter-layerdielectric between conductive interconnects in order to reduce theresistive-capacitive (RC) delay in signal propagation due to capacitiveeffects. As such, the lower the dielectric layer constant of thedielectric, the lower the parasitic capacitance of adjacent conductivelines and the lower the RC delay of the integrated circuit (IC).

However, the materials that are currently being considered or used aslow-k dielectric materials are not ideal. In particular, in choosing amaterial based upon its k-value, and particularly based upon its low-kvalue, other characteristics, such as the hardness of the material orits strength, may not be ideal for use in a semiconductor manufacturingprocess. As such, improvements in processes that utilize low-kdielectric materials are desired.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 illustrates a first dielectric layer, an insert layer, and asecond dielectric layer in accordance with some embodiments.

FIG. 2 illustrates a first opening formed in the second dielectric layerin accordance with some embodiments.

FIGS. 3A-3B illustrate second openings formed in the second dielectriclayer in accordance with some embodiments.

FIG. 4 illustrates a formation of an interconnect in accordance withsome embodiments.

FIG. 5 illustrates an embodiment in which the second openings extendpartially into the insert layer in accordance with some embodiments.

FIGS. 6A-6B illustrate an embodiment in which the second openings extendpartially into the second dielectric layer in accordance with someembodiments.

FIG. 7 illustrates an embodiment which includes the first dielectriclayer and the insert layer and in which the second openings extend intothe first dielectric layer in accordance with some embodiments.

FIG. 8 illustrates an embodiment which includes the first dielectriclayer and the insert layer and in which the second openings extendthrough the insert layer in accordance with some embodiments.

FIG. 9 illustrates an embodiment which includes the first dielectriclayer and the insert layer and in which the second openings extendpartially into the insert layer in accordance with some embodiments.

FIG. 10 illustrates an embodiment which includes the second dielectriclayer and the insert layer and in which the second openings extend intothe insert layer in accordance with some embodiments.

FIG. 11 illustrates an embodiment which includes the second dielectriclayer and the insert layer and in which the second openings extendthrough the second dielectric layer in accordance with some embodiments.

FIG. 12 illustrates an embodiment which includes the second dielectriclayer and the insert layer and in which the second openings extendpartially through the second dielectric layer in accordance with someembodiments.

FIGS. 13-27C illustrate a process flow for utilizing the insert layerwith finFET structures in accordance with some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the invention. Specificexamples of components and arrangements are described below to simplifythe present disclosure. These are, of course, merely examples and arenot intended to be limiting. For example, the formation of a firstfeature over or on a second feature in the description that follows mayinclude embodiments in which the first and second features are formed indirect contact, and may also include embodiments in which additionalfeatures may be formed between the first and second features, such thatthe first and second features may not be in direct contact. In addition,the present disclosure may repeat reference numerals and/or letters inthe various examples. This repetition is for the purpose of simplicityand clarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

With reference now to FIG. 1, FIG. 1 illustrates a substrate 101 withactive devices (not separately illustrated), metallization layers 103over the substrate 101, a conductive element 105 within themetallization layers 103, a first dielectric layer 107, an insert layer109, and a second dielectric layer 111. In an embodiment the substrate101 may comprise bulk silicon, doped or undoped, or an active layer of asilicon-on-insulator (SOI) substrate. Generally, an SOI substratecomprises a layer of a semiconductor material such as silicon,germanium, silicon germanium, SOI, silicon germanium on insulator(SGOI), or combinations thereof. Other substrates that may be usedinclude multi-layered substrates, gradient substrates, or hybridorientation substrates.

The active devices may comprise a wide variety of active devices such astransistors and the like and passive devices such as capacitors,resistors, inductors and the like that may be used to generate thedesired structural and functional parts of the design. The activedevices and passive devices may be formed using any suitable methodseither within or else on the substrate 101.

The metallization layers 103 are formed over the substrate 101 and theactive devices and are designed to connect the various active devices toform functional circuitry for the design. In an embodiment themetallization layers are formed of alternating layers of dielectric andconductive material and may be formed through any suitable process (suchas deposition, damascene, dual damascene, etc.). In an embodiment theremay be one to four layers of metallization separated from the substrate101 by at least one interlayer dielectric layer (ILD), but the precisenumber of metallization layers is dependent upon the design.

The conductive element 105 may be formed in an upper portion of themetallization layers 103, and is a region to which an interconnect 401(not illustrated in FIG. 1 but illustrated and described below withrespect to FIG. 401) will make physical and electrical connection. In anembodiment the conductive element 105 may be a material such as copperformed using, e.g., a damascene or dual damascene process, whereby anopening is formed within an upper portion of the metallization layers103, the opening is filled and/or overfilled with a conductive materialsuch as copper, and a planarization process is performed to embed theconductive material within the metallization layers 103. However, anysuitable material and any suitable process may be used to form theconductive element 105.

The first dielectric layer 107 may be formed in order to help isolatethe interconnect 401 from other adjacent electrical routing lines. In anembodiment the first dielectric layer 107 may be, e.g., a low-kdielectric film intended to help isolate the interconnect 401 from otherstructures. By isolating the interconnect 401, theresistance-capacitance (RC) delay of the interconnect 401 may bereduced, thereby improving the overall efficiency and speed ofelectricity through the interconnect 401.

In an embodiment the first dielectric layer 107 may be a porous materialsuch as SiOCN, SiCN or SiOC and may be formed by initially forming aprecursor layer over the metallization layers 103. The precursor layermay comprise both a matrix material and a porogen interspersed withinthe matrix material, or may alternatively comprise the matrix materialwithout the porogen. In an embodiment the precursor layer may be formed,e.g., by co-depositing the matrix and the porogen using a process suchas plasma enhanced chemical vapor deposition (PECVD) where the matrixmaterial is deposited at the same time as the porogen, thereby formingthe precursor layer with the matrix material and the porogen mixedtogether. However, as one of ordinary skill in the art will recognize,co-deposition using a simultaneous PECVD process is not the only processthat may be used to form the precursor layer. Any suitable process, suchas premixing the matrix material and the porogen material as a liquidand then spin-coating the mixture onto the metallization layers 103, mayalso be utilized.

The precursor layer may be formed to a thickness sufficient to providethe isolation and routing characteristics that are desired of the firstdielectric layer 107. In an embodiment, the precursor layer may beformed to a first thickness T₁ of between about 10 Å and about 1000 Å,such as about 300 Å. However, these thicknesses are meant to beillustrative only, and are not intended to limit the scope of theembodiments, as the precise thickness of the precursor layer may be anysuitable desired thickness.

The matrix material, or base dielectric material, may be formed using aprocess such as PECVD, although any suitable process, such as a chemicalvapor deposition (CVD), physical vapor deposition (PVD), or even spin-oncoating, may alternatively be utilized. The PECVD process may utilizeprecursors such as methyldiethoxy silane (DEMS), although otherprecursors such as other silanes, alkylsilanes (e.g., trimethylsilaneand tetramethylsilane), alkoxysilanes (e.g., methyltriethoxysilane(MTEOS), methyltrimethoxysilane (MTMOS), methyldimethoxysilane (MDMOS),trimethylmethoxysilane (TMMOS) and dimethyldimethoxysilane (DMDMOS)),linear siloxanes and cyclic siloxanes (e.g.,octamethylcyclotetrasiloxane (OMCTS) and tetramethylcyclotetrasiloxane(TMCTS)), combinations of these, and the like may alternatively beutilized. However, as one of ordinary skill in the art will recognize,the materials and processes listed herein are merely illustrative andare not meant to be limiting to the embodiments, as any other suitablematrix precursors may alternatively be utilized.

The porogen may be a molecule that can be removed from the matrixmaterial after the matrix material has set in order to form pores withinthe matrix and thereby reduce the overall value of the dielectricconstant of the first dielectric layer 107. The porogen may be amaterial that is big enough to form the pores while also remaining smallenough such that the size of the individual pores does not overlydisplace the matrix material. As such, the porogen may comprise anorganic molecule such as a methyl containing molecular or an ethylcontaining molecule.

After the precursor layer has been formed with the porogen dispersedwithin the matrix material, the porogen is removed from the matrixmaterial to form the pores within the matrix material. In an embodimentthe removal of the porogen is performed by an annealing process whichcan break down and vaporize the porogen material, thereby allowing theporogen material to diffuse and leave the matrix material, therebyleaving behind a structurally intact porous dielectric material as thefirst dielectric layer 107. For example, an anneal of between about 200°C. and about 500° C., such as about 400° C., for between about 10seconds and about 600 seconds, such as about 200 seconds, may beutilized.

However, as one of ordinary skill in the art will recognize, the thermalprocess described above is not the only method that may be utilized toremove the porogen from the matrix material to form the first dielectriclayer 107. Other suitable processes, such as irradiating the porogenwith UV radiation to decompose the porogen or utilizing microwaves todecompose the porogen, may alternatively be utilized. These and anyother suitable process to remove all or a portion of the porogen are allfully intended to be included within the scope of the embodiments.

However, the first dielectric layer 107 as described above does not havethe desired resistance to withstand unbalanced stress that can occurduring a patterning process. For example, trench openings that arelocated adjacent to a via opening may deform a different amount than atrench opening that is located further away from the via opening, suchas by being the third trench opening removed from the via opening. In aparticular example, each of the trench openings may be patterned with aprocess that attempts to form the trench openings to have a similarwidth, but because of the unbalanced forces within each opening, atrench opening adjacent to the via opening may have that desired widthreduced by 4 nm to 5 nm or 6 nm as compared to the width achieved by atrench opening located away from the via opening. Such reductions anddifferences between the various trench openings could cause gap-fillingproblems in subsequent metallization processes (discussed furtherbelow).

As such, once the first dielectric layer 107 has been formed, the insertlayer 109 is formed over the first dielectric layer 107 in order toprovide a frame for additional structural support to increase therobustness of the first dielectric layer 107 and other subsequentlydeposited layers while impacting the capacitance less than simplychanging the bulk film which would have a thickness of greater than 100{acute over (Å)}. In an embodiment the insert layer 109 is a materialwith a larger hardness and a higher K-value than the first dielectriclayer 107. For example, in an embodiment in which the first dielectriclayer 107 has a hardness of between about 1.5 GPa to about 3.0 GPa, suchas about 2 GPa, the insert layer 109 may have a hardness of greater thanabout 8 GPa, such as between about 10 GPa and about 13 GPa, such asabout 12 GPa. In other words, the insert layer 109 may have a hardnessthat is greater than the first dielectric layer 107 of at least 5 GPa.Similarly, in an embodiment in which the first dielectric layer 107 hasa K-value of between about 2.3 and about 2.9, the insert layer 109 mayhave a K-value of greater than about 3.0.

In particular embodiments, the insert layer 109 may comprise a materialsuch as Si_(x)O_(y) (e.g., SiO₂), Si_(x)O_(y) (e.g., SiO₂), Si_(x)C_(y)(e.g., SiC), Si_(x)N_(y) (e.g., Si₃N₄), Si_(x)O_(y)H_(z) (e.g., SiOH*),and Si_(w)O_(x)C_(y)H_(z) (e.g., SiOCH₃), combinations of these, or thelike. In another embodiment the insert layer 109 may comprise one ormore materials such as metal oxides or metal nitrides, such as aluminumnitride (AlN) or titanium oxide (TiO₂). However, any suitable materialmay be used to provide the additional structural support for the firstdielectric layer 107.

In an embodiment the insert layer 109 may be formed using a depositionprocess such as chemical vapor deposition (CVD), atomic layer deposition(ALD), physical vapor deposition (PVD), or the like. In otherembodiments, such as an embodiment in which SiO₂ if formed, an initiallayer of a first material such as silicon may be deposited or formed,and then the layer may be treated with, e.g., oxygen in order to formthe final material for the insert layer 109. Any suitable process may beused to form the insert layer 109. The insert layer 109 may be formed toa second thickness T₂ of between about 10 {acute over (Å)} and about 100{acute over (Å)}, such as about 30 {acute over (Å)}.

After the insert layer 109 has been formed to provide the additionalsupport, the second dielectric layer 111 may be formed over the insertlayer 109. In an embodiment the second dielectric layer 111 may beformed from a similar material and in a similar fashion as the firstdielectric layer 107. For example, the second dielectric layer 111 maycomprise a porous material such as SiOCN formed by initially placing amatrix material and a porogen and then removing the porogen. However, inother embodiments the second dielectric layer 111 may be a differentmaterial than the first dielectric layer 107. Any suitable combinationof materials may be formed. In an embodiment the second dielectric layer111 may be formed to a third thickness T₃ of between about 100 {acuteover (Å)} and about 600 {acute over (Å)}, such as about 400 {acute over(Å)}.

FIG. 2 illustrates the start of a patterning process to form theinterconnects 401 within the first dielectric layer 107, the insertlayer 109, and the second dielectric layer 111. In an embodiment thepatterning process may be begun by initially applying a firstphotoresist 201, which may include an anti-reflective layer (ARL), ontop of the second dielectric layer 111. Once in place, the firstphotoresist 201 may be exposed to a patterned energy source (e.g.,light) in order to induce a chemical reaction in those portions of thefirst photoresist 201 that are impacted by the energy from the exposure.Once the chemical reaction has induced differences in the physicalproperties between the exposed and the non-exposed regions of the firstphotoresist 201, the first photoresist 201 is developed in order toremove either the exposed portion or the non-exposed portion of thefirst photoresist 201 and to form the pattern within the firstphotoresist 201 and expose an underlying portion of the seconddielectric layer 111.

Once the first photoresist 201 has been placed and patterned, thepattern of the first photoresist 201 is transferred to the underlyingsecond dielectric layer 111 to form a first opening 203 which, in someembodiments, will form an opening for a via. In an embodiment thepattern may be transferred using, e.g., an anisotropic first etchingprocess (represented in FIG. 2 by the wavy line labeled 205) wherebyreactants are directed at the portion of the second dielectric layer 111that has been exposed through the first photoresist 201. In anembodiment the first etching process 205 of removing exposed materialfrom the second dielectric layer 111 may be continued until the insertlayer 109 has been exposed. The first opening 203 may have a first widthW₁ at the top of the second dielectric layer 111 of between about 10 nmand about 50 nm, such as about 30 nm.

If desired, the first etching process 205 may be stopped after theinsert layer 109 has been exposed. Alternatively, the first etchingprocess 205 may be continued so as to remove either all of or a portionof the now exposed portion of the insert layer 109. In an embodiment inwhich the etchants that were utilized to etch the material of the seconddielectric layer 111 are also suitable to etch the material of theinsert layer 109, the first etching process 205 may simply be continuedin order to continue the etch of the material of the insert layer 109.In another embodiment, different etchants or even a different etchingprocess may be utilized in order to pattern the insert layer 109 oncethe insert layer 109 has been exposed. In an embodiment the firstetching process 205 of removing exposed material from the insert layer109 may be continued until the first dielectric layer 107 has beenexposed.

If desired, the first etching process 205 may be stopped after the firstdielectric layer 107 has been exposed. Alternatively, in an embodimentin which all of the exposed portion of the insert layer 109 is removed,the first opening 203 may be extended into the first dielectric layer107. In an embodiment in which the etchants utilized to etch the insertlayer 109 are suitable to etch the first dielectric layer 107, the firstetching process 205 may simply be continued. In another embodiment thefirst etching process 205 may be modified to use different etchants orelse a separate etching process may be utilized to etch the firstdielectric layer 107. In a particular embodiment the first etchingprocess 205 may be continued until the first opening 203 has a firstdepth D₁ within the first dielectric layer 107 of less than about 300{acute over (Å)}, such as about 50 {acute over (Å)}.

FIG. 3A illustrates a removal of the first photoresist 201, a placementof a second photoresist 301, and a second etching process (representedin FIG. 3 by the wavy lines labeled 305) that may be used to both extendthe first opening 203 to expose the conductive element 105 and also toform second openings 303, which in an embodiment may be a trench via. Inan embodiment the first photoresist 201 may be removed using a processsuch as ashing, whereby the temperature of the first photoresist 201 isincreased until the material of the first photoresist 201 undergoes athermal decomposition, at which point it may be removed. However, anyother suitable removal process, such as etching, may also be utilized.

Once the first photoresist 201 has been removed, the second photoresist301 may be applied and patterned. In an embodiment the secondphotoresist 301 may be a similar material and may be patterned asdescribed above with respect to the first photoresist 201. For example,the second photoresist 301 may be applied, exposed to an energy source(e.g., light), and developed in order to form the desired pattern.However, any suitable material or process for forming the secondphotoresist 301 may be used.

Once the second photoresist 301 has been patterned, the second etchprocess 305 is used to form the second openings 303 (which may be, e.g.,openings for conductive trenches) and also to extend the first opening203 (which may be, e.g., a via opening) to expose the conductive element105. In an embodiment the second etch process 305 may be similar to thefirst etching process 205 described above with respect to FIG. 2 withrespect to the first opening 203. For example, the second etchingprocess 305 may be one or more anisotropic etches, such as one or morereactive ion etches, that extend the pattern of the second photoresist301 through the second dielectric layer 111, the insert layer 109,and/or the first dielectric layer 107 to a second depth D₂ of less thanabout 200 {acute over (Å)} such as about 50 {acute over (Å)}. However,any suitable etching process or process may alternatively be utilized.

Additionally, while the second etch process 305 is used to form thesecond openings 303, the second etch process 305 will also work toextend the first opening 203. In particular the second etch process 305is utilized to extend the first opening 203 all of the way through thefirst dielectric layer 107 and expose the underlying conductive element105. Such an exposure of the conductive element 105 allows a portion ofthe interconnects 401 to make physical and electrical contact with theconductive element 105.

However, whereas previous processes (which do not utilize the insertlayer 109) resulted in unbalanced stresses from nearby via etchingprocesses that resulted in a bending of the top opening of trenchesadjacent to the via and caused critical dimension mismatch issuesbetween trench openings at different locations around the device, thepresence of the insert layer 109 will help to prevent the firstdielectric layer 107 and the second dielectric layer 111 from bending orcollapsing. As such, the top of the first openings 203 adjacent to thefirst opening 203 will better retain the desired shape, and secondopenings 303 across the device may have less variation. For example,whereas previous processes without the insert layer 109 may result inbending that could cause variations in widths between different secondopenings 303 (one located adjacent to a via opening and one located awayfrom a via opening) of between about 5 nm to about 6 nm, such as about5.5 nm (or greater than 10% of the desired pattern), the inclusion ofthe insert layer 109 may reduce the amount of bending at the top of thesecond openings 303, such that there may only be a variance betweensecond openings 303 of 0.7 nm to 2.9 nm, such as about 1.7 or about 2 nm(or less than 5% of the desired pattern) in the desired width of thesecond openings 303, for a reduction in variance between differentlylocated second openings 303 (e.g., located adjacent to a via opening bya first length L₁ of between about 5 nm and about 20 nm, such as about10 nm, or located removed from a via opening (shown in dashed withinFIG. 3A by a second length L₂ of between about 50 nm and about 200 nm,such as about 80 nm) of about 3 nm.

Additionally, the presence of the insert layer 109 will cause the secondetching process 305 to form the second openings 303 (e.g., the trenchopenings) to have an angle between the bottom of the second openings 303and a sidewall of the second openings 303. In an embodiment this angle,otherwise known as the trench profile angle α_(TP), may be between about70° to about 80° (instead of a trench profile angle of between 80°-90°without the presence of the insert layer 109).

FIG. 3B illustrates a cross-section view of FIG. 3A along the dashedline in FIG. 3A labeled B-B′ (an “along-line” view) after the secondphotoresist 301 has been removed. In an embodiment the secondphotoresist 301 may be removed using, e.g., an ashing process, althoughany suitable method may be used. Additionally, three first openings 203may be viewed in FIG. 3B, and when the insert layer 109 is present andhelps to provide additional structural support to the second dielectriclayer 111 and prevent it from being disfigured during the patterningprocess, the first openings 203 may each have a via profile angle α_(VP)at the top of the first openings 203 to be between about 60° and about70° (instead of a via profile angle 55°-65° that would occur without theinsert layer 109).

FIG. 4 illustrates a filling of the first opening 203 and the secondopenings 303 with a conductive material to form the interconnects 401.In an embodiment the interconnects 401 comprise vias (e.g., theconductive material within the first opening 203) as well as trenches(e.g., the conductive material within the second openings 303). However,any suitable combination of trenches and vias may be formed.

In an embodiment the first opening 203 and the second openings 303 maybe filled with a barrier layer (not shown) and a conductive material toform the interconnects 401. The barrier layer may comprise a conductivematerial such as titanium nitride, although other materials, such astantalum nitride, titanium, a dielectric, or the like may alternativelybe utilized. The barrier layer may be formed using a CVD process, suchas PECVD. However, other processes, such as sputtering or metal organicchemical vapor deposition (MOCVD), may be used. The barrier layer isformed so as to contour to the underlying shape of the first opening 203and the second openings 303.

The conductive material may comprise copper, although other suitablematerials such as aluminum, alloys, doped polysilicon, combinationsthereof, and the like, may alternatively be utilized. The conductivematerial may be formed by first depositing a seed layer (not separatelyillustrated in FIG. 4) and then electroplating copper onto the seedlayer, filling and overfilling the first opening 203 and the secondopenings 303. Once the first opening 203 and the second openings 303have been filled, excess barrier layer and excess conductive materialoutside of the first opening 203 and the second openings 303 are removedthrough a grinding process such as chemical mechanical polishing (CMP),although any suitable removal process may be used.

Additionally, while the above described process forms the first opening203 prior to forming the second openings 303 in what may be described asa via-first dual damascene process, the embodiments are not limited tothis approach. Rather, any suitable approach for forming the firstopening 203 and second openings 303, such as by utilizing a trench firstdual damascene process, a damascene process, or other suitableinterconnect formation process, may also be utilized. All such processesare fully intended to be included within the scope of the embodiments.

By forming the insert layer 109 to provide additional support for thefirst dielectric layer 107 as well as the second dielectric layer 111,the disfiguration and bending that would normally occur during thepatterning process may be mitigated or prevented. As such, thedeleterious effects of these undesired disfigurations, such as variablereduced widths along a top of the second openings 303, may be prevented.Such preventions allow for fewer defects during the subsequent fillingprocess.

FIG. 5 illustrates another embodiment in which the insert layer 109 isplaced between the first dielectric layer 107 and the second dielectriclayer 111. In this embodiment, however, instead of the second openings303 extending through the insert layer 109 and into the first dielectriclayer 107 (as illustrated above with respect to FIG. 4), the secondetching process 305 may be used to form the second openings 303 toextend only partially through the insert layer 109 and not to extend allof the way through the insert layer 109.

In this embodiment the first dielectric layer 107 may have a fourththickness T₄ of between about 100 {acute over (Å)} and about 700 {acuteover (Å)}, such as about 500 {acute over (Å)}, the insert layer 109 mayhave a fifth thickness T₅ of between about 10 {acute over (Å)} and about100 {acute over (Å)}, such as about 30 {acute over (Å)}, and the seconddielectric layer 111 may have a sixth thickness T₆ of between about 100{acute over (Å)} and about 500 {acute over (Å)}, such as about 300{acute over (Å)}. In this embodiment the second etching process 305 maybe used to form the second openings 303 to extend into the insert layer109 a third depth D₃ of less than about 100 {acute over (Å)}, such asabout 50 {acute over (Å)}.

Once the first opening 203 and the second openings 303 have been formed,the first opening 203 and the second openings 303 may be filled to formthe interconnects 401. In an embodiment the interconnects 401 may beformed as described above with respect to FIG. 4. For example, a barrierlayer and a seed layer may be deposited to line the first opening 203and the second openings 303, and then the first opening 203 and secondopenings 303 may be filled with a conductive material such as copper,and a planarization process may be used to remove excess conductivematerial outside of the first opening 203 and the second openings 303.However, any suitable method and materials may be utilized to form theinterconnects 401.

FIG. 6A illustrates yet another embodiment in which the insert layer 109is placed between the first dielectric layer 107 and the seconddielectric layer 111. In this embodiment the second openings 303 do notextend to the insert layer 109 and remain solely within the seconddielectric layer 111. In this embodiment the first dielectric layer 107may have a seventh thickness T₇ of between about 100 {acute over (Å)}and about 500 {acute over (Å)}, such as about 300 {acute over (Å)}, theinsert layer 109 may have an eighth thickness T₈ of between about 10{acute over (Å)} and about 100 {acute over (Å)}, such as about 30 {acuteover (Å)}, and the second dielectric layer 111 may have a ninththickness T₉ of between about 100 {acute over (Å)} and about 700 {acuteover (Å)}, such as about 500 {acute over (Å)}. In this embodiment thesecond etching process 305 may be used to form the second openings 303to extend into the second dielectric layer 111 a fourth depth D₄ ofbetween about 100 {acute over (Å)} and about 700 {acute over (Å)}, suchas about 500 {acute over (Å)}.

FIG. 6B illustrates a chart comparing the embodiment illustrated in FIG.3A (labeled as “Case-1”), the embodiment illustrated in FIG. 5 (labeledas “Case-2”), and the embodiment illustrated in FIG. 6A (labeled as“Case-3”) against a previous method which only used a single low-kdielectric (labeled “LK only”). In this embodiment the CD bias (thevariance in widths between trench openings adjacent to a via opening(labeled “line(nearby via)”) and trench openings not adjacent to a viaopening (labeled “normal line”) are illustrated by the boxes at thebottom of the graph, while the actual width of the top openings arecharted for each of the cases. As can be seen, without the insert layer109, a variance of 3.6 may be obtained, while the embodiment illustratedin FIG. 3A may achieve an improved variance about of 2.7, the embodimentillustrated in FIG. 5 may achieve an improved variance of about 2, andthe embodiment illustrated in FIG. 6A may achieve a variance of about 0.

FIG. 7 illustrates an embodiment in which the insert layer 109, insteadof being placed between the first dielectric layer 107 and the seconddielectric layer 111, replaces the second dielectric layer 111 such thatthe second dielectric layer 111 is not used. In this embodiment thefirst dielectric layer 107 may be formed with a tenth thickness T₁₀ ofbetween about 100 {acute over (Å)} and about 700 {acute over (Å)}, suchas about 500 {acute over (Å)}, and the insert layer 109 may be formed tohave an eleventh thickness T₁₁ of between about 100 {acute over (Å)} andabout 500 {acute over (Å)}, such as about 300 {acute over (Å)}. In thisembodiment the second etching process 305 may be used to form the secondopenings 303 to extend all of the way through the insert layer 109 andwill extend partially through the first dielectric layer 107. In anembodiment the second openings 303 will extend into the first dielectriclayer 107 a fifth depth D₅ of less than about 300 {acute over (Å)}, suchas about 100 {acute over (Å)}, and will have the trench profile angleα_(TP) of between about 70° to about 80°. Once formed, the first opening203 and the second openings 303 may be filled with conductive materialto form the interconnects 401, as described above with respect to FIG.4.

FIG. 8 illustrates another embodiment in which the insert layer 109,instead of being placed between the first dielectric layer 107 and thesecond dielectric layer 111, replaces the second dielectric layer 111such that the second dielectric layer 111 is not used. In thisembodiment the first dielectric layer 107 may be formed with a twelfththickness T₁₂ of between about 100 {acute over (Å)} and about 600 {acuteover (Å)}, such as about 400 {acute over (Å)}, and the insert layer 109may be formed to have an thirteenth thickness T₁₃ of between about 100{acute over (Å)} and about 700 {acute over (Å)}, such as about 500{acute over (Å)}. Additionally, in this embodiment the second etchingprocess 305 may be used to form the second openings 303 to extend all ofthe way through the insert layer 109 but will not extend into the firstdielectric layer 107. Rather, the second openings 303 will stop at oronly marginally extend into the first dielectric layer 107. Once formed,the first opening 203 and the second openings 303 may be filled withconductive material to form the interconnects 401, as described abovewith respect to FIG. 4.

FIG. 9 illustrates yet another embodiment in which the insert layer 109,instead of being placed between the first dielectric layer 107 and thesecond dielectric layer 111, replaces the second dielectric layer 111such that the second dielectric layer 111 is not used. In thisembodiment the first dielectric layer 107 may be formed with afourteenth thickness T₁₄ of between about 100 {acute over (Å)} and about500 {acute over (Å)}, such as about 300 {acute over (Å)}, and the insertlayer 109 may be formed to have an fifteenth thickness T₁₅ of betweenabout 100 {acute over (Å)} and about 700 {acute over (Å)}, such as about500 {acute over (Å)}. In this embodiment the second etching process 305may be used to form the second openings 303 will extend partiallythrough the insert layer 109 but will not extend all of the way throughthe insert layer 109 and will not extend into the first dielectric layer107. In an embodiment the second openings 303 will extend into theinsert layer 109 a sixth depth D₆ of between about 100 {acute over (Å)}and about 700 {acute over (Å)}, such as about 400 {acute over (Å)}. Onceformed, the first opening 203 and the second openings 303 may be filledwith conductive material to form the interconnects 401, as describedabove with respect to FIG. 4.

FIG. 10 illustrates an embodiment in which, instead of replacing thesecond dielectric layer 111, the insert layer 109 replaces the firstdielectric layer 107, such that the insert layer 109 is formed directlyon the metallization layers 103. In this embodiment the insert layer 109may be formed to have a sixteenth thickness T₁₆ of between about 100{acute over (Å)} and about 700 {acute over (Å)}, such as about 500{acute over (Å)}. Additionally, the second dielectric layer 111 may beformed over the insert layer 109 and have a seventeenth thickness T₁₇ ofbetween about 100 {acute over (Å)} and about 500 {acute over (Å)}, suchas about 300 {acute over (Å)}. In this embodiment the second etchingprocess 305 may be used to form the second openings 303 to extendcompletely through the second dielectric layer 111 and extend partiallythrough the insert layer 109. In an embodiment the second openings 303extend into the insert layer 109 a seventh depth D₇ of less than about300 {acute over (Å)}, such as about 100 {acute over (Å)}. Once formed,the first opening 203 and the second openings 303 may be filled withconductive material to form the interconnects 401, as described abovewith respect to FIG. 4.

FIG. 11 illustrates another embodiment in which, instead of replacingthe second dielectric layer 111, the insert layer 109 replaces the firstdielectric layer 107, such that the insert layer 109 is formed directlyon the metallization layers 103. In this embodiment the insert layer 109may be formed to have an eighteenth thickness T₁₈ of between about 100{acute over (Å)} and about 600 {acute over (Å)}, such as about 400{acute over (Å)}. Additionally, the second dielectric layer 111 may beformed over the insert layer 109 and have a nineteenth thickness T₁₉ ofbetween about 100 {acute over (Å)} and about 700 {acute over (Å)}, suchas about 500 {acute over (Å)}. In this embodiment the second etchingprocess 305 may be used to form the second openings 303 to extendcompletely through the second dielectric layer 111 but to not extend, oronly marginally extend, into the insert layer 109. Once formed, thefirst opening 203 and the second openings 303 may be filled withconductive material to form the interconnects 401, as described abovewith respect to FIG. 4.

FIG. 12 illustrates yet another embodiment in which, instead ofreplacing the second dielectric layer 111, the insert layer 109 replacesthe first dielectric layer 107, such that the insert layer 109 is formeddirectly on the metallization layers 103. In this embodiment the insertlayer 109 may be formed to have a twentieth thickness T₂₀ of betweenabout 100 {acute over (Å)} and about 500 {acute over (Å)}, such as about300 {acute over (Å)}. Additionally, the second dielectric layer 111 maybe formed over the insert layer 109 and have a twenty-first thicknessT₂₁ of between about 100 {acute over (Å)} and about 700 {acute over(Å)}, such as about 500 {acute over (Å)}. In this embodiment the secondetching process 305 may be used to form the second openings 303 toextend partially through the second dielectric layer 111 but not extendall of the way through the second dielectric layer 111. In an embodimentthe second openings 303 extend into the second dielectric layer aneighth depth D₈ of between about 100 {acute over (Å)} and about 700{acute over (Å)}, such as about 400 {acute over (Å)}. Once formed, thefirst opening 203 and the second openings 303 may be filled withconductive material to form the interconnects 401, as described abovewith respect to FIG. 4.

By providing the insert layer as a frame for additional structuralsupport, the normally weaker porous material of the first dielectriclayer 107 and second dielectric layer 111 may be supported. Suchadditional support helps to reduce variances between different trenchesthat may be caused by their proximity (or lack of proximity) to a viaetch process or via opening. This prevents complications that couldarise during subsequent gap-filling processes.

FIG. 13 illustrates an example of a fin field-effect transistor (FinFET)30 in a three-dimensional view that may be used in some embodiments. TheFinFET 30 comprises a fin 36 on a substrate 32. The substrate 32includes isolation regions 34, and the fin 36 protrudes above and frombetween neighboring isolation regions 34. A gate dielectric 38 is alongsidewalls and over a top surface of the fin 36, and a gate electrode 40is over the gate dielectric 38. Source/drain regions 42 and 44 aredisposed in opposite sides of the fin 36 with respect to the gatedielectric 38 and gate electrode 40. FIG. 13 further illustratesreference cross-sections that are used in later figures. Cross-sectionA-A is across a channel, gate dielectric 38, and gate electrode 40 ofthe FinFET 30. Cross-section B/C-B/C is perpendicular to cross-sectionA-A and is along a longitudinal axis of the fin 36 and in a directionof, for example, a current flow between the source/drain regions 42 and44. Subsequent figures refer to these reference cross-sections forclarity.

Some embodiments discussed herein are discussed in the context ofFinFETs formed using a gate-last process. In other embodiments, agate-first process may be used. Also, some embodiments contemplateaspects used in planar devices, such as planar FETs.

FIGS. 14 through 27C are cross-sectional views of intermediate stages inthe manufacturing of FinFETs along with the use of the insert layer 109in accordance with an exemplary embodiment. FIGS. 14 through 18illustrate reference cross-section A-A illustrated in FIG. 13, exceptfor multiple FinFETs. In FIGS. 19A through 27C, figures ending with an“A” designation are illustrated along a similar cross-section A-A;figures ending with a “B” designation are illustrated along a similarcross-section B/C-B/C and in a first region on a substrate; and figuresending with a “C” designation are illustrated along a similarcross-section B/C-B/C and in a second region on a substrate.

FIG. 14 illustrates a substrate 50. Substrate 50 may be a semiconductorsubstrate, such as a bulk semiconductor, a semiconductor-on-insulator(SOI) substrate, or the like, which may be doped (e.g., with a p-type oran n-type dopant) or undoped. The substrate 50 may be a wafer, such as asilicon wafer. Generally, an SOI substrate comprises a layer of asemiconductor material formed on an insulator layer. The insulator layermay be, for example, a buried oxide (BOX) layer, a silicon oxide layer,or the like. The insulator layer is provided on a substrate, typically asilicon or glass substrate. Other substrates, such as a multi-layered orgradient substrate may also be used. In some embodiments, thesemiconductor material of the substrate 50 may include silicon;germanium; a compound semiconductor including silicon carbide, galliumarsenic, gallium phosphide, indium phosphide, indium arsenide, and/orindium antimonide; an alloy semiconductor including SiGe, GaAsP, AlInAs,AlGaAs, GaInAs, GaInP, and/or GaInAsP; or combinations thereof.

The substrate 50 has a first region 50B and a second region 50C. Thefirst region 50B (which corresponds to subsequent figures ending in “B”)can be for forming n-type devices, such as NMOS transistors, such asn-type FinFETs. The second region 50C (which corresponds to subsequentfigures ending in “C”) can be for forming p-type devices, such as PMOStransistors, such as p-type FinFETs.

FIGS. 15 and 16 illustrate the formation of fins 52 and isolationregions 54 between neighboring fins 52. In FIG. 15 fins 52 are formed inthe substrate 50. In some embodiments, the fins 52 may be formed in thesubstrate 50 by etching trenches in the substrate 50. The etching may beany acceptable etch process, such as a reactive ion etch (RIE), neutralbeam etch (NBE), the like, or a combination thereof. The etch may beanisotropic.

In FIG. 16 an insulation material 54 is formed between neighboring fins52 to form the isolation regions 54. The insulation material 54 may bean oxide, such as silicon oxide, a nitride, the like, or a combinationthereof, and may be formed by a high density plasma chemical vapordeposition (HDP-CVD), a flowable CVD (FCVD) (e.g., a CVD-based materialdeposition in a remote plasma system and post curing to make it convertto another material, such as an oxide), the like, or a combinationthereof. Other insulation materials formed by any acceptable process maybe used. An anneal process may be performed once the insulation materialis formed. In the illustrated embodiment, the insulation material 54 issilicon oxide formed by a FCVD process. The insulating material 54 maybe referred to as isolation regions 54. Further in FIG. 5 and in step204, a planarization process, such as a chemical mechanical polish(CMP), may remove any excess insulation material 54 and form topsurfaces of the isolation regions 54 and top surfaces of the fins 52that are coplanar.

FIG. 17 illustrates the recessing of the isolation regions 54 to formShallow Trench Isolation (STI) regions 54. The isolation regions 54 arerecessed such that fins 56 in the first region 50B and in the secondregion 50C protrude from between neighboring isolation regions 54.Further, the top surfaces of the isolation regions 54 may have a flatsurface as illustrated, a convex surface, a concave surface (such asdishing), or a combination thereof. The top surfaces of the isolationregions 54 may be formed flat, convex, and/or concave by an appropriateetch. The isolation regions 54 may be recessed using an acceptableetching process, such as one that is selective to the material of theisolation regions 54. For example, a chemical oxide removal using aCERTAS® etch or an Applied Materials SICONI tool or dilute hydrofluoric(dHF) acid may be used.

A person having ordinary skill in the art will readily understand thatthe process described with respect to FIGS. 15 through 17 is just oneexample of how the fins 56 may be formed. In other embodiments, adielectric layer can be formed over a top surface of the substrate 50;trenches can be etched through the dielectric layer; homoepitaxialstructures can be epitaxially grown in the trenches; and the dielectriclayer can be recessed such that the homoepitaxial structures protrudefrom the dielectric layer to form fins. In still other embodiments,heteroepitaxial structures can be used for the fins. For example, thesemiconductor strips 52 in FIG. 16 can be recessed, and a materialdifferent from the semiconductor strips 52 may be epitaxially grown intheir place. In an even further embodiment, a dielectric layer can beformed over a top surface of the substrate 50; trenches can be etchedthrough the dielectric layer; heteroepitaxial structures can beepitaxially grown in the trenches using a material different from thesubstrate 50; and the dielectric layer can be recessed such that theheteroepitaxial structures protrude from the dielectric layer to formfins 56. In some embodiments where homoepitaxial or heteroepitaxialstructures are epitaxially grown, the grown materials may be in situdoped during growth, which may obviate prior and subsequentimplantations although in situ and implantation doping may be usedtogether. Still further, it may be advantageous to epitaxially grow amaterial in an NMOS region different from the material in a PMOS region.In various embodiments, the fins 56 may comprise silicon germanium(Si_(x)Ge_(1-x), where x can be between approximately 0 and 100),silicon carbide, pure or substantially pure germanium, a III-V compoundsemiconductor, a II-VI compound semiconductor, or the like. For example,the available materials for forming III-V compound semiconductorinclude, but are not limited to, InAs, AlAs, GaAs, InP, GaN, InGaAs,InAlAs, GaSb, AlSb, AlP, GaP, and the like.

In FIG. 17, appropriate wells may be formed in the fins 56, the fins 52,and/or the substrate 50. For example, a P well may be formed in thefirst region 50B, and an N well may be formed in the second region 50C.

The different implant steps for the different regions 50B and 50C may beachieved using a photoresist or other masks (not shown). For example, aphotoresist is formed over the fins 56 and the isolation regions 54 inthe first region 50B. The photoresist is patterned to expose the secondregion 50C of the substrate 50, such as a PMOS region. The photoresistcan be formed by using a spin-on technique and can be patterned usingacceptable photolithography techniques. Once the photoresist ispatterned, an n-type impurity implant is performed in the second region50C, and the photoresist may act as a mask to substantially preventn-type impurities from being implanted into the first region 50B, suchas an NMOS region. The n-type impurities may be phosphorus, arsenic, orthe like implanted in the first region to a concentration of equal to orless than 10¹⁸ cm⁻³, such as in a range from about 10¹⁷ cm⁻³ to about10¹⁸ cm⁻³. After the implant, the photoresist is removed, such as by anacceptable ashing process.

Following the implanting of the second region 50C, a photoresist isformed over the fins 56 and the isolation regions 54 in the secondregion 50C. The photoresist is patterned to expose the first region 50Bof the substrate 50, such as the NMOS region. The photoresist can beformed by using a spin-on technique and can be patterned usingacceptable photolithography techniques. Once the photoresist ispatterned, a p-type impurity implant may be performed in the firstregion 50B, and the photoresist may act as a mask to substantiallyprevent p-type impurities from being implanted into the second region,such as the PMOS region. The p-type impurities may be boron, BF₂, or thelike implanted in the first region to a concentration of equal to orless than 10¹⁸ cm⁻³, such as in a range from about 10¹⁷ cm⁻³ to about10¹⁸ cm⁻³. After the implant, the photoresist may be removed, such as byan acceptable ashing process.

After the implants of the first region 50B and the second region 50C, ananneal may be performed to activate the p-type and n-type impuritiesthat were implanted. The implantations may form a p-well in the firstregion 50B, e.g., the NMOS region, and an n-well in the second region50C, e.g., the PMOS region. In some embodiments, the grown materials ofepitaxial fins may be in situ doped during growth, which may obviate theimplantations, although in situ and implantation doping may be usedtogether.

In FIG. 18, a dummy dielectric layer 58 is formed on the fins 56. Thedummy dielectric layer 58 may be, for example, silicon oxide, siliconnitride, a combination thereof, or the like, and may be deposited orthermally grown according to acceptable techniques. A dummy gate layer60 is formed over the dummy dielectric layer 58, and a mask layer 62 isformed over the dummy gate layer 60. The dummy gate layer 60 may bedeposited over the dummy dielectric layer 58 and then planarized, suchas by a CMP. The mask layer 62 may be deposited over the dummy gatelayer 60. The dummy gate layer 60 may be made of, for example,polysilicon, although other materials that have a high etchingselectivity from the etching of isolation regions 54 may also be used.The mask layer 62 may include, for example, silicon nitride or the like.In this example, a single dummy gate layer 60 and a single mask layer 62are formed across the first region 50B and the second region 50C. Inother embodiments, separate dummy gate layers may be formed in the firstregion 50B and the second region 50C, and separate mask layers may beformed in the first region 50B and the second region 50C.

In FIGS. 19A, 19B, and 19C, the mask layer 62 may be patterned usingacceptable photolithography and etching techniques to form masks 72 inthe first region 50B (as illustrated in FIG. 19B) and masks 78 in thesecond region 50C (as illustrated in FIG. 19C). The pattern of the masks72 and 78 then may be transferred to the dummy gate layer 60 and dummydielectric layer 58 by an acceptable etching technique to form dummygates 70 in the first region 50B and dummy gates 76 in the second region50C. The dummy gates 70 and 76 cover respective channel regions of thefins 56. The dummy gates 70 and 76 may also have a lengthwise directionsubstantially perpendicular to the lengthwise direction of respectiveepitaxial fins.

In FIGS. 20A, 20B, and 20C, gate seal spacers 80 can be formed onexposed surfaces of respective dummy gates 70 and 76 and/or fins 56. Athermal oxidation or a deposition followed by an anisotropic etch mayform the gate seal spacers 80.

After the formation of the gate seal spacers 80, implants for lightlydoped source/drain (LDD) regions may be performed. Similar to theimplants discussed above in FIG. 17, a mask, such as a photoresist, maybe formed over the first region 50B, e.g., NMOS region, while exposingthe second region 50C, e.g., PMOS region, and p-type impurities may beimplanted into the exposed fins 56 in the second region 50C. The maskmay then be removed. Subsequently, a mask, such as a photoresist, may beformed over the second region 50C while exposing the first region 50B,and n-type impurities may be implanted into the exposed fins 56 in thefirst region 50B. The mask may then be removed. The n-type impuritiesmay be any of the n-type impurities previously discussed, and the p-typeimpurities may be any of the p-type impurities previously discussed. Thelightly doped source/drain regions may have a concentration ofimpurities of from about 10¹⁵ cm⁻³ to about 10¹⁶ cm⁻³. An anneal may beused to activate the implanted impurities.

Further in FIGS. 20A, 20B, and 20C, epitaxial source/drain regions 82and 84 are formed in the fins 56. In the first region 50B, epitaxialsource/drain regions 82 are formed in the fins 56 such that each dummygate 70 is disposed between respective neighboring pairs of theepitaxial source/drain regions 82. In some embodiments that epitaxialsource/drain regions 82 may extend into the fins 52. In the secondregion 50C, epitaxial source/drain regions 84 are formed in the fins 56such that each dummy gate 76 is disposed between respective neighboringpairs of the epitaxial source/drain regions 84. In some embodiments thatepitaxial source/drain regions 84 may extend into the fins 52.

Epitaxial source/drain regions 82 in the first region 50B, e.g., theNMOS region, may be formed by masking the second region 50C, e.g., thePMOS region, and conformally depositing a dummy spacer layer in thefirst region 50B followed by an anisotropic etch to form dummy gatespacers (not shown) along sidewalls of the dummy gates 70 and/or gateseal spacers 80 in the first region 50B. Then, source/drain regions ofthe epitaxial fins in the first region 50B are etched to form recesses.The epitaxial source/drain regions 82 in the first region 50B areepitaxially grown in the recesses. The epitaxial source/drain regions 82may include any acceptable material, such as appropriate for n-typeFinFETs. For example, if the fin 56 is silicon, the epitaxialsource/drain regions 82 may include silicon, SiC, SiCP, SiP, or thelike. The epitaxial source/drain regions 82 may have surfaces raisedfrom respective surfaces of the fins 56 and may have facets.Subsequently, the dummy gate spacers in the first region 50B areremoved, for example, by an etch, as is the mask on the second region50C.

Epitaxial source/drain regions 84 in the second region 50C, e.g., thePMOS region, may be formed by masking the first region 50B, e.g., theNMOS region, and conformally depositing a dummy spacer layer in thesecond region 50C followed by an anisotropic etch to form dummy gatespacers (not shown) along sidewalls of the dummy gates 76 and/or gateseal spacers 80 in the second region 50C. Then, source/drain regions ofthe epitaxial fins in the second region 50C are etched to form recesses.The epitaxial source/drain regions 84 in the second region 50C areepitaxially grown in the recesses. The epitaxial source/drain regions 84may include any acceptable material, such as appropriate for p-typeFinFETs. For example, if the fin 56 is silicon, the epitaxialsource/drain regions 84 may comprise SiGe, SiGeB, Ge, GeSn, or the like.The epitaxial source/drain regions 84 may have surfaces raised fromrespective surfaces of the fins 56 and may have facets. Subsequently,the dummy gate spacers in the second region 50C are removed, forexample, by an etch, as is the mask on the first region 50B.

In FIGS. 21A, 21B, and 21C, gate spacers 86 are formed on the gate sealspacers 80 along sidewalls of the dummy gates 70 and 76. The gatespacers 86 may be formed by conformally depositing a material andsubsequently anisotropically etching the material. The material of thegate spacers 86 may be silicon nitride, SiCN, a combination thereof, orthe like.

The epitaxial source/drain regions 82 and 84 and/or epitaxial fins maybe implanted with dopants to form source/drain regions, similar to theprocess previously discussed for forming lightly doped source/drainregions, followed by an anneal. The source/drain regions may have animpurity concentration of in a range from about 10¹⁹ cm⁻³ to about 10²¹cm⁻³. The n-type impurities for source/drain regions in the first region50B, e.g., the NMOS region, may be any of the n-type impuritiespreviously discussed, and the p-type impurities for source/drain regionsin the second region 50C, e.g., the PMOS region, may be any of thep-type impurities previously discussed. In other embodiments, theepitaxial source/drain regions 82 and 84 may be in situ doped duringgrowth.

In FIGS. 22A, 22B, and 22C, an ILD 88 is deposited over the structureillustrated in FIGS. 21A, 21B, and 21C. In an embodiment, the ILD 88 isa flowable film formed by a flowable CVD. In some embodiments, the ILD88 is formed of a dielectric material such as Phospho-Silicate Glass(PSG), Boro-Silicate Glass (BSG), Boron-Doped Phospho-Silicate Glass(BPSG), undoped Silicate Glass (USG), or the like, and may be depositedby any suitable method, such as CVD, or PECVD.

In FIGS. 23A, 23B, and 23C, a planarization process, such as a CMP, maybe performed to level the top surface of the ILD 88 with the topsurfaces of the dummy gates 70 and 76. The CMP may also remove the masks72 and 78 on the dummy gates 70 and 76. Accordingly, top surfaces of thedummy gates 70 and 76 are exposed through the ILD 88.

In FIGS. 24A, 24B, and 24C, the dummy gates 70 and 76, gate seal spacers80, and portions of the dummy dielectric layer 58 directly underlyingthe dummy gates 70 and 76 are removed in an etching step(s), so thatrecesses 90 are formed. Each recess 90 exposes a channel region of arespective fin 56. Each channel region is disposed between neighboringpairs of epitaxial source/drain regions 82 and 84. During the removal,the dummy dielectric layer 58 may be used as an etch stop layer when thedummy gates 70 and 76 are etched. The dummy dielectric layer 58 and gateseal spacers 80 may then be removed after the removal of the dummy gates70 and 76.

In FIGS. 25A, 25B, and 25C, gate dielectric layers 92 and 96 and gateelectrodes 94 and 98 are formed for replacement gates. Gate dielectriclayers 92 and 96 are deposited conformally in recesses 90, such as onthe top surfaces and the sidewalls of the fins 56 and on sidewalls ofthe gate spacers 86, and on a top surface of the ILD 88. In accordancewith some embodiments, gate dielectric layers 92 and 96 comprise siliconoxide, silicon nitride, or multilayers thereof. In other embodiments,gate dielectric layers 92 and 96 include a high-k dielectric material,and in these embodiments, gate dielectric layers 92 and 96 may have a kvalue greater than about 7.0, and may include a metal oxide or asilicate of Hf, Al, Zr, La, Mg, Ba, Ti, Pb, and combinations thereof.The formation methods of gate dielectric layers 92 and 96 may includeMolecular-Beam Deposition (MBD), Atomic Layer Deposition (ALD), PECVD,and the like.

Next, gate electrodes 94 and 98 are deposited over gate dielectriclayers 92 and 96, respectively, and fill the remaining portions of therecesses 90. Gate electrodes 94 and 98 may be made of a metal-containingmaterial such as TiN, TaN, TaC, Co, Ru, Al, combinations thereof, ormulti-layers thereof. After the filling of gate electrodes 94 and 98, instep 228, a planarization process, such as a CMP, may be performed toremove the excess portions of gate dielectric layers 92 and 96 and thematerial of gate electrodes 94 and 98, which excess portions are overthe top surface of the ILD 88. The resulting remaining portions ofmaterial of gate electrodes 94 and 98 and gate dielectric layers 92 and96 thus form replacement gates of the resulting FinFETs.

The formation of the gate dielectric layers 92 and 96 may occursimultaneously such that the gate dielectric layers 92 and 96 are madeof the same materials, and the formation of the gate electrodes 94 and98 may occur simultaneously such that the gate electrodes 94 and 98 aremade of the same materials. However, in other embodiments, the gatedielectric layers 92 and 96 may be formed by distinct processes, suchthat the gate dielectric layers 92 and 96 may be made of differentmaterials, and the gate electrodes 94 and 98 may be formed by distinctprocesses, such that the gate electrodes 94 and 98 may be made ofdifferent materials. Various masking steps may be used to mask andexpose appropriate regions when using distinct processes.

In FIGS. 26A, 26B, and 26C, an ILD 100 is deposited over the ILD 88.Further illustrated in FIGS. 26A, 26B, and 26C, contacts 102 and 104 areformed through ILD 100 and ILD 88 and contacts 106 and 108 are formedthrough ILD 100. In an embodiment, the ILD 100 is a flowable film formedby a flowable CVD method. In some embodiments, the ILD 100 is formed ofa dielectric material such as PSG, BSG, BPSG, USG, or the like, and maybe deposited by any suitable method, such as CVD and PECVD. Openings forcontacts 102 and 104 are formed through the ILDs 88 and 100. Openingsfor contacts 106 and 108 are formed through the ILD 100. These openingsmay all be formed simultaneously in a same process, or in separateprocesses. The openings may be formed using acceptable photolithographyand etching techniques. A liner, such as a diffusion barrier layer, anadhesion layer, or the like, and a conductive material are formed in theopenings. The liner may include titanium, titanium nitride, tantalum,tantalum nitride, or the like. The conductive material may be copper, acopper alloy, silver, gold, tungsten, aluminum, nickel, or the like. Aplanarization process, such as a CMP, may be performed to remove excessmaterial from a surface of the ILD 100. The remaining liner andconductive material form contacts 102 and 104 in the openings. An annealprocess may be performed to form a silicide at the interface between theepitaxial source/drain regions 82 and 84 and the contacts 102 and 104,respectively. Contacts 102 are physically and electrically coupled tothe epitaxial source/drain regions 82, contacts 104 are physically andelectrically coupled to the epitaxial source/drain regions 84, contact106 is physically and electrically coupled to the gate electrode 94, andcontact 108 is physically and electrically coupled to the gate electrode98.

In FIGS. 27A, 27B, and 27C, the first dielectric layer 107, the insertlayer 109, and the second dielectric layer 111 may be formed over theILD 100. Once the first dielectric layer 107, the insert layer 109, andthe second dielectric layer 111 have been formed, the first opening 203,and the second openings 303 may be formed through the first dielectriclayer 107, the insert layer 109, and the second dielectric layer 111 andthen filled with conductive material in order to form the interconnects401 to the contact 106, to the contacts 108, to the contacts 102, and tothe contacts 104. In an embodiment the formation of the interconnects401 within the first dielectric layer 107, an insert layer 109, and asecond dielectric layer 111 may be performed as described above withrespect to FIGS. 1-4. However, any suitable processes or materials maybe utilized to form the interconnects 401.

Additionally, while the embodiments described in FIGS. 13-27C have beendescribed with respect to the first dielectric layer 107, an insertlayer 109, and a second dielectric layer 111 and the interconnects 401as described above with respect to FIGS. 1-4, the embodiments are notintended to be limited to the embodiments described within FIGS. 1-4.Rather, any of the embodiments described above with respect to FIGS.1-12 may be utilized, and all such embodiments are fully intended to beincluded within the scope of the embodiments.

Further, although not explicitly shown, a person having ordinary skillin the art will readily understand that further processing steps may beperformed on the structure in FIGS. 27A, 27B, and 27C. For example,various IMDs and their corresponding metallizations may be formed overthe structure, and external connections may be formed in order toprovide electrical connectivity to the structure.

By utilizing the first dielectric layer 107, the insert layer 109, andthe second dielectric layer 111 as described herein with the structurefor finFETs, additional support for the structure including finFETs maybe obtained. Such additional support helps to reduce variances betweenthe different trenches that may be caused by their proximity (or lack ofproximity) to a via etch process or via opening process, and helps toprevent complications that could arise during subsequent gap-fillingprocesses. As such, a more sturdy structure with fewer defects may becreated for a finFET device.

In accordance with an embodiment, a semiconductor device comprising afirst dielectric layer over a substrate is provided. A second dielectriclayer is in physical contact with the first dielectric layer, whereinthe first dielectric layer and the second dielectric layer form acomposite dielectric layer and wherein the second dielectric layer has alarger hardness than the first dielectric layer; and a first openingextends into the composite dielectric layer, the first opening having anangle of between about 70° to about 80°.

In accordance with another embodiment, a semiconductor device comprisinga first dielectric layer over a substrate, the first dielectric layercomprising a first dielectric material is provided. An insert layer isover and in contact with the first dielectric layer, the insert layercomprising a second dielectric material with a larger hardness and alarger K-value than the first dielectric material. A second dielectriclayer is over and in contact with the insert layer, the seconddielectric layer comprising a third dielectric material with a smallerhardness and smaller K-value than the second dielectric material. Atrench opening is located in the second dielectric layer, the trenchopening having a trench profile angle of between about 70° and about 80°and a via opening is located in the second dielectric layer, the viaopening having a via profile angle of between about 60° and about 70°.

In accordance with yet another embodiment, a method of manufacturing asemiconductor device, the method comprising depositing a firstdielectric layer over a conductive element within a substrate. The firstdielectric layer is supported by depositing an insert layer over and inphysical contact with the first dielectric layer, wherein the insertlayer has a hardness that is greater than the first dielectric layer anda K-value that is greater than the first dielectric layer. A seconddielectric layer is deposited over and in physical contact with theinsert layer, wherein the second dielectric layer has a hardness that isless than the insert layer and has a K-value that is less than theinsert layer. The second dielectric layer, the insert layer, and thefirst dielectric layer are etched to form a via opening, wherein the viaopening has a via profile angle of between about 60° and about 70°, andthe second dielectric layer is etched to form a trench opening at leastpartially into the second dielectric layer, wherein the trench openinghas a trench profile angle of between about 70° and about 80°.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A semiconductor device comprising: a firstdielectric layer over a substrate; a second dielectric layer in physicalcontact with the first dielectric layer, wherein the first dielectriclayer and the second dielectric layer form a composite dielectric layerand wherein the second dielectric layer has a larger hardness than thefirst dielectric layer; and a first opening extending into the compositedielectric layer, the first opening having an angle of between about 70°to about 80°, wherein the first opening is separated from a secondopening by a length of less than about 200 nm.
 2. The semiconductordevice of claim 1, further comprising a third dielectric layer inphysical contact with the second dielectric layer, wherein the thirddielectric layer has a smaller hardness than the second dielectric layerand wherein the first opening extends through the third dielectriclayer.
 3. The semiconductor device of claim 1, further comprising asecond opening extending into the composite dielectric layer, whereinthe first opening is a trench opening and the second opening is a viaopening.
 4. The semiconductor device of claim 3, wherein the via openinghas a via profile angle of between about 60° and about 70°.
 5. Thesemiconductor device of claim 1, wherein the second dielectric layer hasa hardness of at least 5 GPa greater than the first dielectric layer. 6.The semiconductor device of claim 1, wherein the second dielectric layerhas a K-value of greater than about 3.0.
 7. The semiconductor device ofclaim 1, wherein the substrate further comprising a fin.
 8. Asemiconductor device comprising: a first dielectric layer over asubstrate; a second dielectric layer in physical contact with the firstdielectric layer, wherein the first dielectric layer and the seconddielectric layer form a composite dielectric layer and wherein thesecond dielectric layer has a larger hardness than the first dielectriclayer; a third dielectric layer over and in contact with the seconddielectric layer, the third dielectric layer having a smaller hardnessand smaller K-value than the second dielectric layer; a first openingextending into the composite dielectric layer, the first opening havingan angle of between about 70° to about 80°; and a second openingextending into the composite dielectric layer, the second opening beingseparated from the first opening by a distance no greater than about 200nm.
 9. The semiconductor device of claim 8, wherein the first opening isa trench opening and the second opening is a via opening.
 10. Thesemiconductor device of claim 9, wherein the second opening has a viaprofile angle of between about 60° and about 70°.
 11. The semiconductordevice of claim 8, wherein the second dielectric layer has a hardness ofat least 5 GPa greater than the first dielectric layer.
 12. Thesemiconductor device of claim 8, wherein the second dielectric layer hasa K-value of greater than about 3.0.
 13. The semiconductor device ofclaim 8, wherein the substrate further comprises a fin.
 14. Thesemiconductor device of claim 1, wherein the second dielectric layer hasa hardness of between about 10 GPa and about 13 GPa.
 15. Thesemiconductor device of claim 14, wherein the second dielectric layerhas a hardness of between about 10 GPa and about 12 GPa.
 16. Thesemiconductor device of claim 1, wherein the second dielectric layer hasa thickness of between about 10 {acute over (Å)} and about 30 {acuteover (Å)}.
 17. The semiconductor device of claim 1, wherein the firstdielectric layer has a thickness of between about 10 {acute over (Å)}and about 300 {acute over (Å)}.
 18. The semiconductor device of claim 8,wherein the second dielectric layer has a hardness of between about 10GPa and about 13 GPa.
 19. The semiconductor device of claim 16, whereinthe second dielectric layer has a hardness of between about 10 GPa andabout 12 GPa.
 20. The semiconductor device of claim 8, wherein thesecond dielectric layer has a thickness of between about 10 {acute over(Å)} and about 30 {acute over (Å)}.